Signaling device



March 27, 1934. M. c. ARMSTRONG 1,952,351

' SIGNALING DEVICE I I Filed April 23, 1950 V a" 51. 7 1 "34 J y 6 53 52 46 [1V VENTOK MIL 6.127215% {L's A TTORNEY Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE SIGNALING DEVICE York Application April 23, 1930, Serial No. 446,697

2 Claims.

The present invention relates to signaling devices and more particularly to one of the siren type, and has for its object to provide an improved device of this class embodying a practi- 5 cal, efiicient, and compact sound producing signal.

A further object of the invention is to provide improvements in sound producing signals in which a stator and a rotor are employed, and particularly to provide improvements in the driving means for the rotor whereby to effect economy in the cost of operation.

A further object of the invention is to provide an improved signaling device of the siren type in which the rotor is driven by electric clutch means and the latter by a suitable power driven unit with means for rendering the clutch means inoperative at will to permit the rotor to coast after having attained the desired speed.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in v the claims at the end of the specification.

In the drawing:

Fig. 1 is a part sectional elevation of a signaling device embodying the invention with the clutch shown released;

Fig. 2 is a similar view in which the clutch is shown in operating position, and

Fig. 3 is a transverse section taken on line 3a-3a of Fig. 1.

Similar reference numerals throughout the several views indicate the same parts.

The present signaling device is one of the siren type adapted for use on fire apparatus and on various classes of motor vehicles requiring alarm signals of the siren type as well as in industrial plants, and in general wherever the use of a signal of this kind may be required.

The present siren embodies generally a stator and a rotor associated therewith together with electric clutch means for driving the rotor and suitable power means for drivingtheclutchmeans, such for example, as an electric motor. The rotor is so mounted as to be free to continue rotation under its own momentum when the clutch means is disconnected and through intermittent operation of the electric motor or power means for driving the clutch, a saving in the cost of operation is afforded. This is particularly desirable where the current for operating the magnetic clutch and the motor is furnished by a storage battery, as when using the siren on motor vehicles of different classes in different kinds of service re- ,quiring the use of a signal of this type.

While it is preferred to use a storage battery under these conditions of operation, it will be understood that the device may be connected with any current supply source found available or convenient for the purpose.

' Referring to the drawing 10 represents a base or support on which is mounted a frame 11 suitably connected with the base by one or more bolts 12. The frame is provided with a detach- 05' able. extension 13 forming a housing for an electric motor indicated generally at 14. The rear end 15 of the motor shaft is journaled in a hear ing 16 on the end wall 17 of the housing. The opposite end 18 of the motor shaft at a point adj acent the motor is journaled'in a bearing 19 suitably secured in the transverse wall portion 20 of the frame 11. On the forward end of the motor shaft is mounted a rotor, indicated generally at 21 and which operates within the stator 22. The rotor is provided with a hub 22a in which are positioned front and rear ball bearings 23 and 24, respectively, which are free to rotate on the motor shaft; The outer ring sections of the front and rear bearings are respectively held in position by plate members 25 and 26 suitably secured to the hub 22a. Thrust members are provided for the bearings in the form of sleeves 27 and 28 positioned on the shaft 18, and a collar 29 thereon is secured by a nut 30 threaded 85. upon the outer extremity of the motor shaft.

The rotor 21 is loosely fitted within the stator and is provided with a suitable number of slots 31 in its peripheral wall which cooperate with corresponding slots 32 in the peripheral wall of the stator, the slots of the rotor lying between the radially extending blades 31a of the rotor.

It will be understood that when the rotor is driven at a relatively high speed that the air drawn in by it and forced against its inner circumferential surface will escape through the peripheral slots both of the rotor and the stator in the usual manner. The blasts of air thus intermittently ejected in rapid succession will produce a loud and more or less penetrating sound, the pitch of which varies according to the speed at which the rotor is driven. Protection is afforded from the revolving rotor by a shield 33 on the front of the stator which has a plurality of openings 34 for the passage of the air to the rotor.

The frame 11 is provided with a housing 35 which is preferably formed integral therewith and also integral with the stator as shown in Fig. 1. Disposed within the housing is a driving device for, the rotor comprising electric clutch Gil means which is suitably energized preferably by the passage of an electric current therethrough. The clutch comprises an annular frame element or drum like member 36 keyed on the motor shaft for rotation thereby within the housing 35, theframe element having secured thereto a magnet 37 preferably in the form of a magnetic coil housed within the frame element. The movable member of the clutch is preferably in the form of a disk 38 supported on the rear face of the rotor by a plurality of guide pins 39 suitably secured to the rotor. The clutch disk is normally held disengaged by a plurality of springs 40 secured to the rear wall of the rotor by means of screws 41 which when loosened permit the springs to be swung to one side or the other for the purpose of releasing the disk when it is desired to remove the same. The disk and the driving element 3'? are respectively provided with annular or ring shaped members 42 and 43 which are preferably formed of hardened brass or bronze. The disk acts as an armature and is moved rearwardlybythe attraction of the magnetic vcoil 3'? when energized, so that the ring 42 is moved and held in frictional engagement with the driving ring 43 as long as the coil remains energized by the current flowing therethrough. Ihe friction between the rings 42 and 43 is sufficient to drive the rotor, which rotates on the ball bearings-shown on the outer end of the motor shaft. As soon as the clutch circuit is broken the springs 40 will return the disk to normal position as shown in" Fig; 1, and the momentum of the rotor will'cause it to coast for a considerable time, the speed gradually decreasing, and likewise the pitch of the more or less penetrating sound produced by the air escaping through the Walls of the siren.

The annular frame element 36 is provided with a continuous contact 44 in the form of a metal band which is spaced fromthe frame element by a member 45 formed of insulating material. A contact element '46 extends into engagement with the band and is adjustably supported in a hollow plug 47 screwed into the wall of the clutch housing 35.

Current for operating the motor and the magnetic clutch, the circuits of which are in parallel, may be supplied from any suitable source, such for example, as a storage battery 48. Circuit connections :are interposed between the battery and the clutch and motor which are indicated more or less diagrammatically in Fig. 1. The clutch circuit is completed through wires 49 and 50 by pressing the switch button 51 to move contact member 52 into engagement with contactmember 53.so that the current will flow from one side of the battery to the other passing through the coil 37 to ground and causing the driving disk for the rotor to move to operating position, as shown in Fig. 2. Completion of the motor circuit will be effected by further depressing the switch button until contact member 53 is moved into engagement with a third contact member 54 having a wire 55 leading to the motor terminal 56 extending through the motor casing 5'7, as indicated in'Fig. 1.

It is preferred to close the clutch circuit slightly in advance of the motor circuit to insure engagement of the clutch before completion of the motor circuit and the switch is therefore shown constructed to accomplish this result, although if desired the contacts of the switch may be so arranged as to'close both circuits at the same time or either in advance of the other.

The construction of the present signaling device is such as to facilitate a comparatively easy and rapid assembly of the parts and removal thereof as well at such times as it may be found necessary to make repairs. When the motor has been positioned within the frame the driving unit of the clutch is inserted upon the motor shaft and keyed thereon, after which the spacing sleeve 58 is inserted between said element and the motor shaft bearing 19. The thrust member 56 is then inserted upon the shaft following which the rotor and its bearings and the sleeve 28 are applied in the proper order, and all being held in position by the collar 29 and nut 30 on the outer extremity of the motor shaft. While it is preferred to extend the motor shaft and to mount the rotor thereon, it will be understood that if desired the rotor may be mounted on a separate bearing or support for operation by the clutch in the manner described.

In the operation of the present sound producing device it is only necessary to hold the switch closed long enough for the motor and rotor driven thereby to attain the desired speed, after which the circuit is broken and the rotor allowed to coast to complete the sounding of the siren. By thus using the current of the battery or other supply source for short periods only, economy in the cost of operation is effected, and this is particularly advantageous when a storage battery is employed to operate the siren.

I claim:

l. Asiren of the class described, comprising an electric motor having its shaft extending therefrom, a stator surrounding the outer extended portion of the shaft, a rotor journalecl on said extended shaft portion within the stator, a clutch comprising a driving part keyed on the shaft between the motor and the rotor and including an electromagnet, an operating part for driving the rotor disposed adjacent the rear wall of the rotor, means on said wall for supporting and guiding said operating part, said part being moved into engagement with the driving part by said electro-magnet upon energizing the latter, and means for returning the operating part to inoperative position when the electromagnet is deenergized.

2. A siren of the class described, comprising an electric motor, a housing at one end of the motor provided with an extension forming a stator, said housing having a transverse wall adjacent the motor through which the motor shaft is extended into the stator, a bearing on said wall rotatably supporting the shaft, a rotor journaled upon the shaft within the stator, a clutch within the housing between said transverse wall and the rotor comprising a relatively heavy driving part fixed on the motor shaft for rotation thereby, said driving part being provided with a recess and having an electromagnet therein, guides mounted upon the rotor and extending in the direction of said driving part, a driving disk for the rotor supported by said guides for movement into engagement with the driving part by the electromagnet upon energizing the latter, and spring means operating upon said driving disk to disengage it from the driving part when said electromagnet is deenergized, said rotor upon release of the disk being free to coast upon the motor shaft and said relatively heavy driving part operating asa flywheel after opening the motor circuit whereby to prolong rotation of the motor shaft in the direction of rotation of the rotor.

MERTON C. ARMSTRONG. 

